We present a method for arbitrary control of the polarization of a light beam. Our method uses two holograms on a binary ferroelectric liquid crystal spatial light modulator (FLCSLM), and so has the potential to allow polarization state switching at kilohertz rates. Unlike previous methods that achieve polarization control using FLCSLMs, our method is common path and requires only the simplest optical components. For this reason, the method is very easy to setup, align, and maintain. In addition, it has the ability to modulate unpolarized input light. We demonstrate the formation of radially, azimuthally, and circularly polarized beams by imaging their focal spots formed at low numerical aperture.
This paper reports the development, modelling and application of a semi-random multicore fibre (MCF) design for adaptive multiphoton endoscopy. The MCF was constructed from 55 sub-units, each comprising 7 single mode cores, in a hexagonally close-packed lattice where each sub-unit had a random angular orientation. The resulting fibre had 385 single mode cores and was double-clad for proximal detection of multiphoton excited fluorescence. The random orientation of each sub-unit in the fibre reduces the symmetry of the positions of the cores in the MCF, reducing the intensity of higher diffracted orders away from the central focal spot formed at the distal tip of the fibre and increasing the maximum size of object that can be imaged. The performance of the MCF was demonstrated by imaging fluorescently labelled beads with both distal and proximal fluorescence detection and pollen grains with distal fluorescence detection. We estimate that the number of independent resolution elements in the final image - measured as the half-maximum area of the two-photon point spread function divided by the area imaged - to be ~3200.
We suggest a mixed reality display in which the eye-box follows the eye's pupil by shearing of the holographic combiner. Tests on Bragg gratings show a switching extinction ratio of 35:1 for an extrapolated shear of several microns and switching energy of milliJoules or less.
The demand for long-term data storage in the cloud grows continuously into the zettabytes. Operating at such scales requires a fundamental re-thinking of how we build large-scale storage systems to archive data in a sustainable and costeffective manner. In Project Silica, a storage technology for the cloud is being designed and developed from the media up by leveraging the recent progress in ultrafast laser nano-structuring of the transparent media. Together with the advances in reading, decoding and error correction processes, high-density and high-throughput multi-dimensional volumetric optical data writing is achieved, enabling successful end-to-end proof-of-concept demonstrations of the technology. With exceptional media longevity, this could transform archival cloud storage. Here we briefly discuss the development of the technology, key metrics for cost-efficient optical data storage at scale, and successful proof-ofconcept demonstrations.
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